C. elegans show Preference for Pseudomonas mendocina (MSPm1) and Proteus mirabilis ( P. mirabilis sp?) , and Repulsion to Pseudomonas lurida (MYb11); Growth on Pseudomonas mendocina (MSPm1) Increases Attraction to 2-nonanone

C. elegans’ experiences and microbiome have been shown to shape its responses to certain stimuli; a recent study found that C. elegans grown on Providencia alcalifaciens JUb39 exhibited increased attraction to that same growth bacteria while also lowered repulsion to the odor 1-octanol (O’Donnell et al. 2020). This prompted us to ask whether other strains of bacteria could likewise alter C. elegans’ responses to bacterial food and volatile chemicals. So, to expand upon current knowledge, we cultured wild-type C. elegans (N2) on an unidentified Escherichia coli ( E. coli sp?), Pseudomonas mendocina (MSPm1), Pseudomonas lurida (MYb11), Stenotrophomonas maltophilia (JUb19), or Proteus mirabilis strain ( P. mirabilis sp?). After several generations, we examined how their choice of bacterial food was affected. In addition, we looked at their response to the olfactory stimuli 2-butanone; 2,3-butanedione; 2,3-pentanedione; and 2-nonanone, as well as their response to the gustatory stimulus sodium chloride. Interestingly, we found that growth on any of these bacterial strains led to their bacterial preferences and behavioral responses to 2-butanone; 2,3-pentanedione; diacetyl; and sodium chloride remaining unchanged. However, we also saw that C. elegans showed a preference for MSPm1 and P. mirabilis sp? to HB101, and HB101 to MYb11. Furthermore, worms that are grown on MSPm1 showed stronger attraction to a 1:10 dilution of 2-nonanone (AWB-sensed odorant) as compared to worms grown on the other bacterial strains.